<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>制作圆圈环已经半圆</title>
    <style type="text/css">
        div.box{
            width: 200px;
            height: 100px;
            background-color: white;
            /* border-top-left-radius: 15px;
            border-top-right-radius: 15px; */
            /* border-radius: 50%; */
            border-top-left-radius: 100px;
            border-top-right-radius: 100px;
            border: 5px solid pink;
        }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
</html>